Is there any hope?!?

So about 5 mins ago I had to use a public toilet. It's shared as I'm in a camp site. Anyway I walked into the first cubicle only to smell vomit and there was a thin layer of it in the toilet water. I walked out and used another cubicle but now I'm panicking! I'm hoping that it is just a teenager has drank too many wkds or something but if it is a sickness bug is there any way I can prevent catching it? I've thoroughly washed my hands and basically doused myself in hand sanitiser but could really do without catching a bug whilst on holiday! Any suggestions welcome.